南瓜籽中N/蛋白质含量检测方案(氮磷钙测定仪)

APPLICATION NOTEF&F-D-001-2019/A1 N/Protein Determination in Pumpkin Seedaccording to the Dumas method (He/Ar as Carrier) Reference： AOAC 992.23 Crude Protein in Cereal Grains and Oil seeds Tested with VELP Scientifica NDA 702 Dual Carrier Gas Dumas Nitrogen Analyzer (Code F30800080) Introduction Pumpkin seeds are nutrient-rich， with especially high content of protein， dietary fiber and numerous micronutrients. ThesIrseeds have long been valued as a source of the mineral zinc， and the World Health Organization recommends theirconsumption as a good way of obtaining this nutrient. Pumpkin seeds are a common ingredient in Mexican cuisine andthey are typically rather flat and asymmetrically oval， and light green in color and may have a white outer hull. The oil ofpumpkin seeds， a culinary specialty and important export commodity of Central Europe， is used in cuisine as a salad andcooking oil. DC Protein Determination in Pumpkin seed The Dumas method starts with a combustion furnace (CF)， obtaining amixture of gas molecules： Water is removed by a first physical trap (WT1-DriStepTM)， placedafter the combustion， and a second chemical one (WT2).Between thetwo， the elemental substances passed through a reduction furnace(RF). The auto-regenerative CO2 adsorbers let pass only the elementalnitrogen that is detected by the LoGasTM innovative ThermalConductivity Detector (TCD) with no requirement for a reference gas.The NDA 702 is controlled via PC through the intuitive DUMASoft TM. NDA 702 Preliminary Operations (daily) Follow the operating manual to start the NDA 702 and check that the following parameters are set： Temperature Combustion reactor (Code A00000158)：1.030°C Temperature Reduction reactor (Code A00000226)：650°C Flow rate MFC1 (He/Ar)： 190 ml/min Flow rate MFC2 (He/Ar)： 220 ml/min Condition the system by testing 2 EDTA standard (Code A00000149) and 3 to 5 empty tin foils (Code A00000153) ascheck up. Verify the calibration curve with one or more tests as Standard by testing the same standard used for the curve creation Sample Preparation Pumpkin seed Expected Protein range： 28-30% Remove the peel of the seed， if necessary. Grind the test samples using a grinder to suitable fineness (particle size ≤ 0.5 mm) to obtain ≤2，0 % relative standarddeviation (RSD) for 10 successive nitrogen determinations. Weigh around 100 mg of the homogeneous sample directly into the tin foil directly on the balance. Close the tin foil， obtaining a capsule and load it into the autosampler. Analysis Procedure .Fill the following fields in the database： Sample name， Weight， Method， Sample type， Calibration number The PUMPKIN SEED method shows the following parameters： Protein factor： 6.25 O2 flow rate： 400 ml/min O2 factor： 1.4 ml/mg Press to start the analysis. Analysis time： from 3 minutes for one run. Results on Pumpkin seed Results have been obtained with the following calibration curve： in a range of 0 - 10 mg N with 5 measurements of EDTAstandard (N%=9.57) (Code A00000149) for both carrier gases. The data obtained are included in the tolerance admitted by the EDTA certificate. The accuracy of NDA 702 has been demonstrated through 10 successive analysis of nicotinic acid as indicated in theofficial method AOAC 992.23. HELIUM as Carrier Gas ARGON as Carrier Gas Sample quantity (mg) Protein% Sample quantity (mg) Protein% 99.76 28.812 100.11 28.844 99.96 29.003 99.98 29.226 99.90 28.826 99.92 28.397 100.01 29.165 99.84 28.847 100.05 28.611 99.86 28.714 100.14 28.908 103.60 28.432 100.17 28.959 101.50 28.724 100.06 28.833 98.90 29.345 100.12 28.806 100.80 28.834 100.05 28.338 102.00 29.147 Average± SD 28.826±0.225 Average±SD 28.851±0.314 RSD%* 0.781 RSD%* 1.089 Protein Expected Value： 28-30 % Protein Factor： 6.25 Protein Factor： 6.25 *RSD%=(Standard Deviation* 100)/ Average Conclusion Results are extremely reliable， as demonstrated by the RSD， both using helium and argon as carrier gas， with the sameconditions (method and sample weight) since the goal is to obtain < 2.0% relative standard deviation， as requested byofficial methods. Helium remains the best choice for premium accuracy but its shortages and interruptions are affecting any related productor instrument， including elemental analyzers. Argon， the best alternative available， has demonstrated to be a validsubstitute， ensuring optimal results. VELP Scientifica NDA 702 Dual Carrier Gas Dumas Nitrogen Analyzer is the perfect response to simple， fast and precisenitrogen/protein determination， both with Helium and Argon as carrier gas. Benefit of N/Protein determination with VELP Elementar Analyzer NDA 702 are： e Excellent accuracy and precision ● Low cost per analysis Fast and easy to use Analyzer Cloud connection to VELP Ermes to access the data and the instrument in real time， everywhere. 南瓜籽营养丰富，蛋白质、膳食纤维及多种微量营养素含量特别高。这种种子长期以来一直被认为是矿物质锌的来源，世界卫生组织推荐食用这种种子，认为这是获取这种营养的好方法。南瓜籽是墨西哥菜中常见的配料，通常呈扁平的不对称椭圆形，颜色呈淡绿色，外皮可能为白色。南瓜籽油是中欧的一种烹饪特产和重要的出口商品，在烹饪中用作沙拉和食用油。检测样品：南瓜籽（Pumpkin seed）  预期的蛋白质范围：28-30 %检测仪器：意大利VELP    NDA 702双载气杜马斯定氮仪参照标准：AOAC 992.23 谷物和油料种子的粗蛋白质实验结果：通过以下校准曲线获得了结果:在0 - 10 mg N范围内，对两种载气进行了5次EDTA标准测量(N% = 9.57)(代码A00000149)。获得的数据包含在EDTA证书认可的公差中。实验结论：RSD结果非常可靠，使用氦气和氩气作为载气，在相同的条件(方法和样品重量)下，因为目标是获得低于2.0%的相对标准偏差，按照官方方法的要求。氦仍然是高精确度的最佳选择，但它的短缺和中断正在影响任何相关产品或仪器，包括元素分析仪。氩气，可用的最佳替代品，已被证明是有效的替代品，确保最佳结果。  意大利VELP NDA 702双载气杜马斯定氮仪是简单，快速和精确的氮/蛋白质测定仪器，以氦和氩作为载气。